Radial nerve in the middle third of the shoulder. Radial artery, veins and superficial branch of the radial nerve

The radial nerve is one of the largest nerves brachial plexus. Moves down the back wall humerus, innervating the triceps brachii and forearm muscles. Also provides sensitivity directly to the skin of the shoulder, forearm, lower and upper side of the thumb. This nerve is mixed; it provides motor function of the arm, extension, abduction and adduction.

Damage to the radial nerve is a pathology in any area characterized by a specific origin. It manifests itself in the form of a drooping hand and the inability to independently straighten the hand or elbow joint. It may also be caused by loss of sensation in the shoulder area.

A nerve consists of nerve fibers, which in turn have three segments. From the brachial plexus the radial nerve gives off a branch at the level pectoral muscle. In the armpit area it thickens significantly. But after moving away from the armpit, approximately in the area of ​​the middle of the shoulder, it becomes significantly thinner. In this case, innervation occurs only in the zones of the hand and forearm. The largest accumulation of nerve bundles occurs in the armpit, and the smallest in the region of the third of the shoulder.

The radial nerve has branches:

• Articular - tends to the shoulder joint;
• Posterior cutaneous nerve - innervates the skin of the back of the shoulder;
• The lower lateral cutaneous nerve of the shoulder - moves next to the previous one, but still branches in the skin of the lateral and lower third of the shoulder;
• The branches of the muscles are divided into proximal (located closer to the center), lateral (or side) and medial (middle). These branches innervate the triceps muscle, the ulnar muscle, as well as the radial and brachial muscles;
• The posterior cutaneous nerve of the forearm passes in the region of the axillary and brachial canal. Spreads many nerve branches to the skin;
• The branch is superficial and is the final branch in the region of the humeroradial joint. Strives to the back of the hand, where it gives innervation to the skin of the inner side of the 1st, 2nd and central side of the 3rd finger;
• It is deep, passes through the arch support in the area of ​​the neck of the radius and exits onto the inner side of the forearm. At this point, there is a breakdown into many muscle branches that provide sensitivity to the extensor muscles.

Neuropathy

Damage to the radial nerve occurs quite often. It can be damaged by squeezing or an awkward position of the hand during sleep, injury, or fracture. When walking for a long time on crutches and during compression with hooks during operations. Disruption of innervation can also be observed due to compression by a tumor extending from neighboring tissue. Malignancy is extremely rare in this location.

Damage to the ulnar nerve is fraught with disorders of the motor functions of the hand.

If the elbow is severely injured, active flexion and extension of the fingers is temporarily impossible. Atrophy may develop over several months interosseous muscles. You can notice the appearance of the metacarpal bones on the inside of the palm. The middle phalanges often take a bent position. If the damage concerns the shoulder area, then the extensors of the middle phalanges are affected. A contusion to the ulnar plexus does not impair the function of the triceps muscle at all. But if the wrist part is damaged, it suffers first inner part palms. Painful sensations not observed with this injury. However, the back of the hand swells and becomes cold.

Damage to the median nerve leads to disruption and even loss of sensitivity at the site of its innervation. The skin in this area becomes shiny, thin and dry. The nails of the first three fingers are cross-striated. Lesions of the median nerve below lead to paralysis of the base of the thumb, and if the upper part is affected, the flexor palmaris is impaired. The motor function of the thumb is almost completely impaired. The consequence of this process is muscle atrophy. If the injury is old enough, more than a year, then restoration of the innervation of the hand is impossible.

If neuralgia of the radial nerve concerns the axillary region, the extensor functions of the forearm and hand suffer. A “falling” or “hanging” hand syndrome occurs. The back of the hand and the phalanges of 1-3 fingers suffer.

The cause of nerve damage can be fractures of the bones of the upper shoulder girdle, as well as when applying a tourniquet. In rare cases, the cause may be an incorrect injection into the shoulder. The above reasons also include injuries of various types or a strong blow.

Another risk factor may be various intoxications, bacterial and viral infections, or lead poisoning.

Diagnostics

One of the main tasks of neuralgia is correct diagnosis. The disease develops abruptly, with acute pain. The symptoms and signs of the lesions are very similar to each other. It is quite difficult to differentiate between damage to the ulnar and median nerves. A number of neurological tests are used for correct diagnosis.

What tests are used for diagnosis:

• Hands touch each other internal parties palms, fingers straightened. Then, simultaneously, each finger is moved away from each other. In the place where the nerve lesion is present, palmar flexion of the fingers is observed;
• In the next test, the doctor asks you to shake his hand or make a fist; in case of neurological disorders, the “dangling” hand syndrome appears;

Various functional tests to determine sensitivity make it possible to differentiate ulnar neuropathy from radial and median nerve neuropathy.

Violations are divided into primary and secondary. Primary - acquired as a result of bruises or when a tumor compresses neighboring tissues. Secondary ones include, for example, tissue swelling or transformation of a nerve into a scar. There are separate (isolated) and mixed (vascular involvement in the pathological process). Symptoms depend on the area of ​​damage and the very nature of the pathological process.

Treatment

What to do if the radial nerve is damaged? Immediately consult a doctor for an accurate diagnosis of the affected area. If you conduct a neurological examination in time and treat the disease with the provided regimen, then recovery will be quite quick and effective. Traditionally, therapy will be aimed at relieving pain and restoring the damaged area. Medications include:

• non-steroidal anti-inflammatory drugs;
• vitamins, complex, group B and calcium supplements;
• painkillers blockades, for example, novocaine;
• analgesics;
• diuretic drugs.

Often the complex of conservative treatment includes physiotherapy, physical therapy, acupuncture and massages. If, after applying complex treatment for several months, no improvement is observed, then the doctor has to suture the nerve. It's already radical methods treatment. These include the removal of tumors at the site of compression of the nerve. It is advisable to resort to surgical intervention in case of combined damage to the nerve and bone or vessel. Such operations are performed in several stages. A common indication for surgical intervention is neurolysis. This is the release of the nerve from scar tissue. Surgeries are considered more effective with early intervention.

• Place the arm in a bent position on a hard surface so that the forearm is perpendicular to this surface. We lift our thumb up and pull our thumb down. Repeat the exercise – 10 times;
• We do the exercise in the same way as in the previous description, but the middle and index fingers are used. Repeat the exercise 10 times;
• We unclench and compress various objects. One approach – 10 times.

Therapeutic gymnastics and massage contribute to more rapid recovery motor function of the upper shoulder girdle.

Table of contents of the topic "Posterior shoulder area. Anterior elbow area. Posterior ulnar area.":
1. Posterior region of the shoulder. External landmarks of the posterior region of the shoulder. Borders of the posterior region of the shoulder. Projection onto the skin of the main neurovascular formations of the posterior region of the shoulder.
2. Layers of the posterior shoulder area. Posterior fascial bed of the shoulder. Proprietary fascia of the shoulder.
3. Topography of the neurovascular bundle of the posterior region of the shoulder. Topography of the radial nerve (n. radialis). Connection of the tissue of the posterior region of the shoulder with neighboring areas.
4. Anterior elbow area. External landmarks of the anterior ulnar region. Borders of the anterior ulnar region. Projection onto the skin of the main neurovascular formations of the anterior ulnar region.
5. Layers of the anterior ulnar region. Veins of the ulnar region. Topography of superficial (subcutaneous) formations of the anterior ulnar region.
6. Own fascia of the anterior ulnar region. Pirogov's muscle. Fascial beds of the anterior ulnar region.
7. Topography of the neurovascular formations of the anterior ulnar region. Topography of deep (subfascial) formations of the anterior ulnar region.
8. Posterior elbow area. External landmarks of the posterior ulnar region. Borders of the posterior ulnar region. Projection onto the skin of the main neurovascular formations of the posterior ulnar region.
9. Layers of the posterior ulnar region. Synovial bursa of the olecranon process. Topography of the neurovascular formations of the posterior ulnar region. Topography of the posterior ulnar region.

Topography of the neurovascular bundle of the posterior region of the shoulder. Topography of the radial nerve (n. radialis). Connection of the tissue of the posterior region of the shoulder with neighboring areas.

Radial nerve comes to the posterior surface of the shoulder from the anterior fascial bed through the gap between the long and lateral heads of the triceps muscle. Further, it is located in the brachial muscular canal, canalis humeromuscularis, which spirals around the humerus in its middle third. One wall of the canal is formed by bone, the other by the lateral head of the triceps muscle (Fig. 3.18).

In the middle third of the shoulder canalis humeromuscularis radial nerve is adjacent directly to the bone, which explains the occurrence of paresis or paralysis after applying a hemostatic tourniquet to the middle of the shoulder for a long time or in cases of damage to it due to fractures of the diaphysis of the humerus.

Together the deep brachial artery goes with the nerve, a. profunda brachii, which soon after its onset gives off the ramus deltoi-deus, which is important for collateral circulation between the areas of the shoulder girdle and shoulder, anastomosing with the deltoid branch of the thoracoacromial artery and with the arteries around the humerus. In the middle third of the shoulder a. profunda brachii is divided into two terminal branches: a. collateralis radialis and a. collateralis media. Radial nerve together with a. collateralis radialis at the border of the middle and lower third of the region pierces the lateral intermuscular septum and returns to the anterior bed of the shoulder, and then to the anterior ulnar region. There the artery anastomoses with a. recurrent radialis. A. collateralis media anastomoses with a. interossea recurrences.

In the lower third of the shoulder in the posterior fascial bed The ulnar nerve passes from a. collateralis ulnaris superior. Next they are directed to the posterior elbow area.

Rice. 3.18. Posterior shoulder 1 - m. infraspinatus; 2 - m. teres minor; 3 - m. teres major, 4 - a. brachialis; 5 - r. muscularis a. profundae brachii; 6 - n. cutaneus brachii medialis; 7 - m. triceps brachii (caput longum); 8 - r. muscularis n. radialis; 9 - m. triceps brachii (caput laterale); 10 - m. triceps brachii (caput mediale); 11 - tendo m. tricipitis brachii; 12 - n. ulnaris et a. collateralis ulnaris superior, 13 - n. cutaneus antebrachii posterior; 14 - a. collateralis media; 15 - m. anconeus; 16 - m. flexor carpi ulnaris; 17 - m. trapezius; 18 - spina scapulae; 19 - m. deltoideus; 20 - n. axillaris et a. circumflexa humeri posterior, 21 - a. ciicumflexa scapulae; 22 - humerus; 23 - n. radialis et a. profunda brachii.

Connection of the tissue of the posterior region of the shoulder with neighboring areas

1. Along the radial nerve proximally the fiber is connected with the fiber of the anterior fascial bed of the shoulder.

2. Distally- with fiber of the ulnar fossa.

3. Along the long head of the triceps brachii muscle it is associated with the fiber of the axillary fossa.

Educational video of the anatomy of the axillary, brachial arteries and their branches

The radial nerve is formed from the posterior bundle of the brachial plexus and is a derivative of the ventral branches of the CV - CVIII spinal nerves. The nerve descends along the posterior wall of the axilla, located behind the axillary artery and located sequentially on the abdomen subscapularis muscle and on tendons latissimus muscle back and teres major muscle. Having reached the brachiomuscular angle between internal part shoulder and the lower edge of the posterior wall of the axilla, the radial nerve is adjacent to a dense connective tissue band formed by the connection of the lower edge of the latissimus dorsi muscle and the posterior tendon of the long head of the triceps brachii muscle. Here is the site of possible, especially external, compression of the radial nerve. The nerve then lies directly on the humerus in the groove of the radial nerve, otherwise called the spiral groove. This groove is limited by the places of attachment to the bone of the external and internal heads of the triceps brachii muscle. This forms the radial nerve canal, also called the spiral, brachioradial or brachiomuscular canal. In it, the nerve describes a spiral around the humerus, passing from the inside and back in the anteriolateral direction. The spiral canal is the second site of potential compression of the radial nerve. From it on the shoulder branches go to the triceps brachii muscle and the olecranon muscle. These muscles extend the upper limb at the elbow joint.

A test to determine their strength: the examinee is asked to straighten a limb that is previously slightly bent at the elbow joint; the examiner resists this movement and palpates the contracted muscle.

The radial nerve at the level of the outer edge of the shoulder at the border of the middle and lower thirds of the shoulder changes the direction of its course, turns in front, pierces the external intermuscular septum, passing into the anterior compartment of the shoulder. Here the nerve is especially vulnerable to compression. Below, the nerve passes through the initial part of the brachioradialis muscle: it also innervates the long extensor carpi radialis and descends between it and the brachialis muscle.

The brachioradialis muscle (innervated by the CV - CVII segment) flexes the upper limb at the elbow joint and pronates the forearm from a supinated position to a midline position.

A test to determine its strength: the subject is asked to bend the limb at the elbow joint and at the same time pronate the forearm from the supination position to the middle position between supination and pronation; the examiner resists this movement and palpates the contracted muscle.

The long extensor carpi radialis (innervated by the CV - CVII segment) extends and abducts the hand.

Test to determine muscle strength: they ask you to straighten and abduct the hand; the examiner resists this movement and palpates the contracted muscle. Having passed brachialis muscle, the radial nerve crosses the capsule elbow joint and approaches the instep support. In the ulnar region, at the level of the lateral epicondyle of the shoulder or a few centimeters above or below it, the main trunk of the radial nerve is divided into superficial and deep branches. The superficial branch goes from the subbrachioradialis muscle to the forearm. In its upper third, the nerve is located outward from the radial artery and above the styloid process of the radius passes through the gap between the bone and the tendon of the brachioradialis muscle to the dorsal surface of the lower end of the forearm. Here this branch divides into five dorsal digital nerves (nn. Digitales dorsales). The latter branch in the radial half of the dorsal surface of the hand from the nail phalanx of the first, middle phalanx of the second and radial half of the third fingers.

The deep branch of the radial nerve enters the gap between the superficial and deep bundles of the supinator and is directed to the dorsum of the forearm. The dense fibrous upper edge of the superficial fascicle of the arch support is called the arcade of Froese. Under the arcade of Froese is also the site of the most likely occurrence of radial nerve tunnel syndrome. Passing through the supinator canal, this nerve is adjacent to the neck and body of the radius and then exits onto the dorsum of the forearm, under the short and long superficial extensors of the hand and fingers. Before exiting the dorsum of the forearm, this branch of the radial nerve supplies the following muscles.

1. The extensor carpi radialis brevis (innervated by the CV-CVII segment) is involved in wrist extension.
2. The supinator (innervated by the CV-CVIII segment) rotates and supinates the forearm.

A test to determine the strength of this muscle: the subject is asked to supinate the limb extended at the elbow joint from a pronated position; the examiner resists this movement.

On the dorsum of the forearm, the deep branch of the radial nerve innervates the following muscles.

The extensor digitorum (innervated by the CV-CVIII segment) extends the main phalanges of the II-V fingers and at the same time the hand.

A test to determine its strength: the subject is asked to straighten the main phalanges of the II - V fingers, when the middle and nail ones are bent; the examiner resists this movement.

The extensor carpi ulnaris (innervated by segment CVI - CVIII) extends and adducts the wrist.

A test to determine its strength: the subject is asked to straighten and adduct the hand; the examiner resists this movement and palpates the contracted muscle. The continuation of the deep branch of the radial nerve is the dorsal interosseous nerve of the forearm. It passes between the extensors of the thumb to the wrist joint and sends branches to the following muscles.

The abductor pollicis longus muscle (innervated by segment CVI - CVIII) abducts the first finger.

A test to determine its strength: the subject is asked to abduct and slightly straighten the finger; the examiner resists this movement.

The extensor pollicis brevis (innervated by segment CVI-CVIII) extends the main phalanx of the first finger and abducts it.

Test to determine its strength: the subject is asked to straighten the main phalanx of the first finger; the examiner resists this movement and palpates the tense tendon of the muscle.

The extensor pollicis longus (innervated by segment CVII-C VIII) extends the nail phalanx of the first finger.

Test to determine its strength: the subject is asked to straighten the nail phalanx of the first finger; the examiner resists this movement and palpates the tense tendon of the muscle.

Extensor index finger(innervated by the CVII-CVIII segment) extends the index finger.

Test to determine its strength: the subject is asked to straighten the second finger; the examiner resists this movement.

The extensor of the little finger (innervated by the CVI - CVII segment) extends the fifth finger.

Test to determine its strength: the subject is asked to straighten the fifth finger; the examiner resists this movement.

The posterior interosseous nerve of the forearm also gives off thin sensory branches to the interosseous septum, periosteum of the radius and ulna, back surface carpal and carpometacarpal joints.

The radial nerve is predominantly motor and supplies mainly the muscles that extend the forearm, hand, and fingers.

To determine the level of damage to the radial nerve, you should know where and how the motor and sensory branches arise from it. The posterior cutaneous nerve of the shoulder branches into the region of the axillary exit. It supplies the dorsum of the shoulder almost to the olecranon. The posterior cutaneous nerve of the forearm is separated from the main trunk of the nerve at the brachioaxillary angle or in the spiral canal. Regardless of the location of the branch, this branch always passes through the spiral canal, innervating the skin of the posterior surface of the forearm. The branches to the three heads of the triceps brachii muscle arise in the area of ​​the axillary fossa, the brachioaxillary angle and the spiral canal. The branches to the brachioradialis muscle usually arise below the spiral canal and above the lateral epicondyle of the shoulder. The branches to the extensor carpi radialis longus usually arise from the main trunk of the nerve, although below the branches to the previous muscle, but above the supinator. The branches to the extensor carpi radialis brevis may arise from the radial nerve, its superficial or deep branches, but also usually above the entrance to the supinator canal. Nerves to the supinator can branch above or at the level of this muscle. In any case, at least part of them passes through the arch support channel.

Let us consider the levels of damage to the radial nerve. At the level of the brachioaxillary angle, the radial nerve and the branches that arise from it in the axillary fossa to the triceps brachii muscle can be pressed against the dense tendons of the latissimus dorsi and pectoralis major muscles in the tendon angle of the axillary exit area. This angle is limited by the tendons of these two muscles and the long head of the triceps brachii muscle. Here, external compression of the nerve can occur, for example, due to improper use of a crutch - the so-called “crutch” paralysis. The nerve may also be compressed by the back of a chair for office workers or by the edge of an operating table over which the shoulder hangs during surgery. Compression of this nerve implanted under the skin is known chest driver heart rate. Internal compression of the nerve at this level occurs with fractures of the upper third of the shoulder. Symptoms of damage to the radial nerve at this level are distinguished primarily by the presence of hypoesthesia on the posterior surface of the shoulder, to a lesser extent by weakness of forearm extension, as well as the absence or decrease in the reflex from the triceps brachii muscle. When the upper limbs are stretched forward to a horizontal line, a “dangling or falling hand” is revealed - a consequence of paresis of extension of the hand in the wrist joint and the II - V fingers in the metacarpophalangeal joints.

In addition, there is weakness in extension and abduction of the first finger. Supination of the extended upper limb also fails, whereas with preliminary flexion at the elbow joint, supination is possible due to the biceps muscle. Elbow flexion and pronation of the upper limb is impossible due to paralysis of the brachioradialis muscle. Muscle wasting of the dorsal surface of the shoulder and forearm may be detected. The hypoesthesia zone includes, in addition to the posterior surface of the shoulder and forearm, the outer half of the dorsum of the hand and the first finger, as well as the main phalanges of the second and radial half of the third finger. Compression of the radial nerve in the spiral canal usually results from a fracture of the humerus in the middle third. Nerve compression may occur soon after a fracture due to tissue swelling and increased pressure in the canal. Later, the nerve suffers when it is compressed by scar tissue or callus. With spiral canal syndrome, there is no hypoesthesia in the shoulder. As a rule, it does not suffer and triceps shoulder, since the branch to it is located more superficially - between the lateral and medial heads of this muscle - and is not directly adjacent to the bone. In this tunnel, the radial nerve is displaced along the long axis of the humerus during contraction of the triceps muscle. The callus formed after a shoulder fracture can prevent such movements of the nerve during muscle contraction and thereby contribute to its friction and compression. This explains the occurrence of pain and paresthesia on the dorsal surface of the upper limb during extension in the elbow joint against the action of a resistance force for 1 minute with incomplete post-traumatic damage to the radial nerve. Painful sensations can also be caused by finger compression for 1 minute or by tapping the nerve at the level of compression. Otherwise, symptoms similar to those noted with damage to the radial nerve in the region of the brachioaxillary angle are revealed.

At the level of the external intermuscular septum of the shoulder, the nerve is relatively fixed. This is the site of the most common and simplest compression lesion of the radial nerve. It is easily pressed against the outer edge of the radius during deep sleep on a hard surface (gloss, bench), especially if the head presses against the shoulder. Due to fatigue, and more often in a state alcohol intoxication the person does not wake up in time, and the function of the radial nerve is turned off (“sleepy” paralysis, “garden bench paralysis”). With “sleep paralysis” there is always motor loss, but there is never weakness of the triceps brachii muscle, i.e. paresis of forearm extension and decreased reflex from the triceps brachii muscle. Some patients may experience loss of not only motor functions, but also sensory ones, but the zone of hypoesthesia does not extend to the back surface of the shoulder.

In the lower third of the shoulder above the lateral epicondyle, the radial nerve is covered by the brachioradialis muscle. Here the nerve can also be compressed when the lower third of the humerus is fractured or when the head of the radius is displaced.

Symptoms of damage to the radial nerve in the supracondylar region may be similar to sleep paralysis. However, in the nervous case there is no isolated loss of motor functions without sensory ones. The mechanisms of occurrence of these types of compression neuropathies are also different. The level of nerve compression approximately coincides with the location of the shoulder injury. Determining the upper level of provoking pain on the dorsum of the forearm and hand during tapping and digital compression along the projection of the nerve also helps in differential diagnosis.

In some cases, it is possible to determine compression of the radial nerve by the fibrous arch lateral head m. triceps. The clinical picture corresponds to the above. Pain and numbness on the back of the hand in the area supplying the radial nerve may periodically intensify with intense manual work, while running long distances, with sharp flexion of the upper limbs at the elbow joint. This causes compression of the nerve between the humerus and the triceps muscle. It is recommended that such patients pay attention to the angle of flexion in the elbow joint when running and stop manual labor.

A fairly common cause of lesions of the deep branch of the radial nerve in the area of ​​the elbow joint and upper forearm is compression by a lipoma or fibroma. They can usually be palpated. Removal of the tumor usually leads to recovery.

Among other causes of damage to the branches of the radial nerve, mention should be made of bursitis and synovitis of the elbow joint, especially in patients with rheumatoid polyarthritis, a fracture of the proximal head of the radius, traumatic vascular aneurysm, and professional overexertion with repeated rotational movements of the forearm (conducting, etc.). Most often, the nerve is affected in the canal of the supinator fascia. Less commonly, it occurs at the level of the elbow joint (from the radial nerve between the brachialis and brachioradialis muscles to the head of the radius and flexor carpi radialis longus), which is referred to as radial tunnel syndrome. The cause of compression-ischemic damage to the nerve may be the fibrous band in front of the head of the radius, the dense tendon edges of the short extensor carpi radialis or the arcade of Froese.

Supinator syndrome develops when the posterior interosseous nerve is damaged in the area of ​​the arcade of Froese. It is characterized by night pain in the outer parts of the elbow area, on the back of the forearm and, often, on the back of the wrist and hand. Daytime pain usually occurs during manual work. Rotational movements of the forearm (supination and pronation) especially contribute to the appearance of pain. Patients often note weakness in the hand that appears during work. This may be accompanied by poor coordination of hand and finger movements. Local tenderness is detected upon palpation at a point located 4 - 5 cm below the external epicondyle of the shoulder in the groove radial to the long extensor carpi radialis.

Tests are used that cause or increase pain in the hand, for example, a supination test: both palms of the subject are tightly fixed on the table, the forearm is bent at an angle of 45 ° and placed in the position of maximum supination; the examiner tries to move the forearm to a pronated position. This test is performed for 1 minute; it is considered positive if pain appears on the extensor side of the forearm during this period.

Middle finger extension test: pain in the hand can be caused by prolonged (up to 1 min) extension of the third finger with resistance to extension.

There is weakness in supination of the forearm, extension of the main phalanges of the fingers, and sometimes there is no extension in the metacarpophalangeal joints. Paresis of abduction of the first finger is also detected, but extension of the terminal phalanx of this finger is preserved. When the functions of the extensor brevis and abductor pollicis longus muscles are lost, radial abduction of the hand in the plane of the palm becomes impossible. With an extended wrist, deviation of the hand to the radial side is observed due to loss of function of the extensor carpi ulnaris, while the long and short extensor carpi radialis are intact.

The posterior interosseous nerve may be compressed at the level of the middle or lower part of the supinator dense connective tissue. Unlike the “classical” supinator syndrome, caused by compression of the nerve in the area of ​​the arcade of Froese, in the latter case the symptom of digital compression is positive at the level of the lower, rather than the upper, edge of the muscle. In addition, paresis of finger extension with “lower supinator syndrome” is not combined with weakness of forearm supination.

The superficial branches of the radial nerve at the level of the lower forearm and wrist may be compressed by a tight watch strap or handcuffs (“prisoner's palsy”). However, the most common cause of nerve damage is injury to the wrist and lower third of the forearm.

Compression of the superficial branch of the radial nerve during a fracture of the lower end of the radius is known as “Thurner syndrome,” and damage to the branches of the radial nerve in the area of ​​the anatomical snuffbox is called radial carpal tunnel syndrome. Compression of this branch is a common complication of de Quervain's disease (ligamentitis of the first canal of the dorsal carpal ligament). The extensor brevis and abductor longus muscles of the first finger pass through this canal.

When the superficial branch of the radial nerve is affected, patients often experience numbness on the back of the hand and fingers; Sometimes there is a burning pain on the back of the first finger. The pain may spread to the forearm and even the shoulder. In the literature, this syndrome is called Wartenberg paresthetic neuralgia. Sensitive loss is often limited to the hypoesthesia path on the inner back side of the first finger. Often, hypoesthesia can extend beyond the first finger to the proximal phalanges of the second finger and even to the rear of the main and middle phalanges of the third and fourth fingers.

Sometimes the superficial branch of the radial nerve thickens at the wrist. Finger compression of such a “pseudoneuroma” causes pain. The tapping symptom is also positive when tapping along the radial nerve at the level of the anatomical snuffbox or the styloid process of the radius.

The differential diagnosis of radial nerve damage is carried out with spinal root syndrome CVII, in which, in addition to weakness of extension of the forearm and hand, paresis of shoulder adduction and flexion of the hand is detected. If motor loss is absent, the location of pain should be taken into account. When the CVII root is damaged, pain is felt not only on the hand, but also on the dorsum of the forearm, which is not typical for damage to the radial nerve. In addition, radicular pain is provoked by head movements, sneezing, and coughing.

Thoracic outlet level syndromes are characterized by the occurrence or intensification of painful sensations in the arm when turning the head to the healthy side, as well as when performing some other specific tests. At the same time, the pulse in the radial artery may decrease. It should also be taken into account that if at the level of the thoracic outlet the part of the brachial plexus corresponding to the CVII root is compressed, then a picture similar to the lesion of this root described above will arise.

Electroneuromyography helps determine the level of damage to the radial nerve. You can limit yourself to research using needle electrodes of the triceps brachii, brachioradialis, extensor digitorum and extensor index finger muscles. With supinator syndrome, the first two muscles will be preserved, and in the last two, during their complete voluntary relaxation, spontaneous (denervation) activity may be detected in the form of fibrillation potentials and positive sharp waves, and also with maximum voluntary muscle tension - the absence or decrease of potentials motor units. When the radial nerve on the shoulder is irritated, the amplitude of the muscle action potential from the extensor of the index finger is significantly lower than when the nerve is electrically stimulated below the supinator channel on the forearm. Establishing the level of damage to the radial nerve can also be helped by studying latent periods - the time of conduction of a nerve impulse and the speed of propagation of excitation along the nerve. To determine the speed of excitation propagation along the motor fibers of the tympanic nerve, electrical stimulation is carried out in various points. The most high level irritation is the Botkin-Erb point, located several centimeters above the collarbone in the posterior triangle of the neck, between the posterior edge of the sternocleidomastoid muscle and the collarbone. Below, the radial nerve is irritated at the point of exit from the axillary fossa in the groove between the coracobrachialis muscle and the posterior edge of the triceps brachii muscle, in the spiral groove at the level of the middle of the shoulder, as well as at the border between the lower and middle third of the shoulder, where the nerve passes through the intermuscular septum, even more distally - 5 - 6 cm above the external epicondyle of the shoulder, at the level of the elbow (humeroradial) joint, on the back of the forearm 8 - 10 cm above the wrist or 8 cm above the styloid process of the radius. Recording electrodes (usually concentric needles) are inserted into the site of maximum response to stimulation of the nerve of the triceps muscle - brachialis, brachialis, brachioradialis, extensor digitorum, extensor index finger, extensor pollicis longus, abductor longus or extensor pollicis brevis. Despite some differences in the points of stimulation of the nerve and the places where the muscle response is recorded, normally similar values ​​of the speed of propagation of excitation along the nerve are obtained. Its lower limit for the neck-armpit area is 66.5 m/s. On a long section from the supraclavicular Botkin-Erb point to the lower third of the shoulder average speed sometimes 68-76 m/s. In the area “axillary fossa - 6 cm above the external epicondyle of the shoulder” the speed of propagation of excitation is on average 69 m/s, and in the area “6 cm above the external epicondyle of the shoulder - the forearm is 8 cm above the styloid process of the radius” - 62 m/s at abduction of muscle potential from the extensor of the index finger. From this it can be seen that the speed of excitation propagation along the motor fibers of the radial nerve in the shoulder is approximately 10% higher than in the forearm. The average values ​​on the forearm are 58.4 m/s (fluctuations are from 45.4 to 82.5 m/s). Since lesions of the radial nerve are usually unilateral, taking into account individual differences in the speed of propagation of excitation along the nerve, it is recommended to compare the indicators on the diseased and healthy sides. By examining the speed and time of conduction of the nerve impulse from the neck to the various muscles innervated by the radial first, it is possible to differentiate the pathology of the plexus and different levels of nerve damage. Lesions of the deep and superficial branches of the radial nerve are easily distinguished. In the first case, only pain occurs in the upper limb and motor loss can be detected, but superficial sensitivity is not impaired.

In the second case, not only pain is felt, but also paresthesia, there is no motor loss, but superficial sensitivity is impaired.

It is necessary to differentiate compression of the superficial branch in the ulnar region from its involvement at the level of the wrist or lower third of the forearm. The area of ​​pain and sensitive loss may be the same. However, the voluntary forced extension test of the wrist will be positive if the superficial branch is compressed only at the proximal level as it passes through the extensor carpi radialis brevis. Tests with tapping or digital compression along the projection of the superficial branch should also be carried out. The upper level, at which these effects cause paresthesia on the back of the hand and fingers, is the likely site of compression of this branch. Finally, the level of nerve damage can be determined by injecting 2 - 5 ml of a 1% solution of novocaine or 25 mg of hydrocortisone into this place, which leads to a temporary cessation of pain and/or paresthesia. If the nerve block is performed below the point of compression, the intensity of the pain will not change. Naturally, pain can be temporarily relieved by blocking the nerve not only at the level of compression, but also above it. To distinguish between distal and proximal lesions of the superficial branch, 5 ml of 1% novocaine solution is first injected at the border of the middle and lower third of the forearm at its outer edge. If the block is effective, this indicates a lower level of neuropathy. If there is no effect, a repeated block is performed, but in the area of ​​the elbow joint, which relieves pain and indicates the upper level of damage to the superficial branch of the radial nerve.

Diagnosis of the location of compression of the superficial branch can also be helped by studying the spread of excitation along the sensory fibers of the radial nerve. The conduction of a nerve impulse through them is completely or partially blocked at the level of compression of the superficial branch. With a partial blockade, the time and speed of propagation of excitation along the sensory nerve fibers slow down. Various research methods are used. With the orthodromic technique, excitation along the sensory fibers spreads towards the conduction of the sensitive impulse. To do this, stimulating electrodes are placed on the limb more distally than the abducent electrodes. With the antidromic technique, the spread of excitation along the fibers in the opposite direction is recorded - from the center to the periphery. In this case, the proximal electrodes located on the limb are used as stimulating ones, and the distal electrodes are used as discharge electrodes. The disadvantage of the orthodromic technique, compared to the antidromic one, is that with the former, lower potentials are recorded (up to 3 - 5 μV), which may be within the noise limits of the electromyograph. Therefore, the antidromic technique is considered more preferable.

It is better to place the most distal electrode (stimulating in the orthodromic technique and abducting in the antidromic technique) not on the dorsum of the first finger. and in the area of ​​the anatomical snuffbox, approximately 3 cm below the styloid process, where a branch of the superficial branch of the radial nerve passes over the tendon of the extensor pollicis longus. In this case, the amplitude of the response is not only higher, but also subject to less individual fluctuations. The same advantages are applied to the distal electrode not on the first finger, but on the space between the first and second metatarsal bones. The average speed of excitation propagation along the sensory fibers of the radial nerve in the area from the leaf electrodes to the lower parts of the forearm in the orthodromic and antidromic directions is 55-66 m/s. Despite individual fluctuations, the speed of excitation propagation along the symmetrical sections of the nerves of the limbs in individuals on both sides is approximately the same. Therefore, it is not difficult to detect a slowdown in the speed of propagation of excitation along the fibers of the superficial branch of the radial nerve when it is unilaterally damaged. The speed of excitation propagation along the sensory fibers of the radial nerve is somewhat different in individual areas: from the spiral groove to the ulnar region - 77 m/s, from the ulnar region to the middle of the forearm - 61.5 m/s, from the middle of the forearm to the wrist - 65 m/s , from the spiral groove to the middle of the forearm - 65.7 m/s, from the elbow to the wrist - 62.1 m/s, from the spiral groove to the wrist - 65.9 m/s. A significant slowdown in the rate of propagation of excitation along the sensory fibers of the radial nerve on its two upper segments will indicate a proximal level of neuropathy. Similarly, the distal level of damage to the superficial branch can be detected.

], , ,

Superficial veins: lateral saphenous vein of the arm. medial saphenous vein of the arm. “M”-shaped type of anastomosis. - intermediate medial saphenous vein,. intermediate lateral saphenous vein. “I”-shaped type of anastomosis - intermediate vein of the elbow..

Superficial nerves: medial cutaneous nerve of the forearm. lateral cutaneous nerve of the forearm.

Venipuncture: Venesection: performed when long-term infusions are necessary when venipuncture is impossible, .1 moment - isolating the vein, .2 moment - placing ligatures under the isolated vein. 3rd moment - dissection of the anterior wall of the vein and its catheterization. after which the proximal ligature is tied to the catheter. and the distal ligature is used to tie the peripheral end of the vein. Step 4 - suturing the wound with interrupted silk sutures.

TOPOGRAPHY OF THE RADIAL NERVE

Radial nerve The shoulder, together with the deep brachial artery and its branches along the upper and middle third of the shoulder, is located in a spiral canal. This canal is formed anteriorly by the groove of the radial nerve of the humerus. behind - the triceps brachii muscle. The proximity of the radial nerve of the shoulder to the bone explains its damage by bone fragments during a fracture or its involvement in the callus. paralysis and paresis can be observed when a hemostatic tourniquet is applied. especially when applying it in the middle third. because here the nerve is in most close contact with the bone. therefore, the tourniquet should be applied correctly in the upper third of the shoulder. where the contact of the radial nerve and the humerus is less pronounced.

The radial nerve at the border with the axillary fossa lies behind the brachial artery, then passes between the long and medial heads of the triceps muscle into a spiral canal. Having circled the bone in the lower third of the shoulder, the nerve appears on its outer surface between the brachialis and brachioradialis muscles. Innervates the triceps muscle, brachioradialis and gives off cutaneous branches to the posterior surface of the shoulder and forearm. Projection line – from the middle of the rear edge deltoid muscle to the lower end of the lateral groove of the biceps muscle.

TOPOGRAPHY OF THE ULNA NERVE

Ulnar nerve

The ulnar nerve passes into the ulnar groove from the posterior ulnar region between the heads of the flexor carpi ulnaris, it gives motor branches to this muscle and to the ulnar part of the deep flexor digitorum. In the middle third of the forearm, the palmar branch and the dorsal branch depart from the ulnar nerve, which bends inwards, passes between the ulna and ulnar flexor wrist, penetrates the own fascia of the forearm and, at the border with the wrist, moves to the back of the hand

TOPOGRAPHY OF THE MIDDLE NERVE

In the upper third of the forearm, the nerve lies between the heads of the pronator teres, crosses the ulnar artery in front, passes between the superficial and deep flexor fingers and in the lower third reaches the median groove. The median nerve supplies motor branches to the pronator teres, flexor carpi radialis, and longus palmaris muscle, flexor digitorum superficialis, flexor digitorum profundus radialis, flexor longus first finger, gives off the anterior interosseous nerve and the palmar cutaneous rope.

Median nerve lies in the canalis carpalis along with the tendons of the superficial and deep flexor muscles and m.flexor pollicis longus. Its branches are under the PLD, next to it are palmar branches of n.ulnaris. From them depart nn.digitales palmares communes, which are divided into their own. digital nerves (those exit from the KO to the fingers).

“Forbidden zone” is a place of departure. from the median nerve branch to the thenar muscles (projected onto the proximal half of the thenar).

In lat. goes to the side superficial palmar branch of a.radialis. On honey the elbow goes to the side. s-dy and nerves (in canalis carpi ulnaris).

In the fiber near LA nah-sya superficial palmar arch (arranged by the a.ulnaris, the edges anastomose with the superficial palmar branch of the a.radialis) – lies in the middle of the 3rd metacarpal bone. 3 aa.digitales palmares co-mmunes depart from it, which, having exited through the KO, anastomose with the metacarpal arteries (from the GLD) and divide into their own digital arteries (which supply there are sides of 2-5 fingers facing each other. The little finger receives a branch from a.ulnaris (before the formation of the arch), and the thumb and 1/2 of the index finger - from a.prin-ceps pollicis (branch of a.radialis) .

Deep palmar arch lies proximal to the PLD on the interosseous muscles under the flexor tendons (separated from them by fiber and deep fascia). It is formed due to the a.radialis, the edges are analogous to the deep palmar branch of the a.ulna-ris. Aa.metetarseae palmares depart from the arch (which then anastomose with the dorsal ones of the same name and flow into aa.digitales palmares communes

In the neurology of “mononeuropathies,” one of the main problems is the problem of determining the “level of nerve damage,” since an adequate clinical expert assessment of the severity of the disease and its prognosis, as well as the adequate development of treatment and preventive measures, depends on the “adequacy of its solution.” Let us consider the basic principles of “level” diagnosis of neuropathy using the example of the radial nerve (n. radialis). It must first be noted that a “level” diagnosis of neuropathy is advisable only in the absence of clear indications of the level of influence of an exogenous provoking factor (for example, a fracture of the “ray in a typical place” or a fracture of the humerus at the level of its c/3), which requires identification level of nerve pathology according to the basic principles of topical diagnostics in neurology (in particular, according to the “level principle”), as well as in the differential diagnosis of causes limiting one or another action in a limb - pathology of the musculoskeletal system or a “purely neurogenic” cause (for example, the pathology of the superficial branch of the radial nerve in a fracture of the radius in the lower part, i.e. in a fracture of the radius in a “typical place” will never cause limitations in the extension of the hand and fingers, but will only cause pathological deficit or irritative phenomena). Before moving on to the level diagnosis (and its principles) of the pathology of the radial nerve, it is necessary, firstly, to consider the course of the radial nerve and its main (“ramal”) dichotomies, secondly, to consider the muscles and areas of the skin that innervate the radial nerve, and thirdly, correlate the first with the second, then decide at what level which muscles and areas of the skin innervate the radial nerve (its branches).

Course of the radial nerve : the radial nerve is formed from the [secondary] posterior brachial plexus and is a derivative of the ventral branches of the CV - CVIII spinal nerves; along the posterior axillary cavity, the nerve descends down, located in the axillary artery and located sequentially on the belly of the subscapularis muscle, on the tendons of the latissimus dorsi muscle and the teres major muscle; Having reached the brachioaxillary angle between the inner part of the shoulder and the lower edge of the posterior wall of the axillary cavity, the radial nerve is adjacent to a dense connective tissue band formed by the connection of the lower edge of the latissimus dorsi muscle and the posterior tendon part of the long head of the triceps brachii muscle (in the area where the radial nerve exits the axillary fossa from its the main trunk gives off the posterior cutaneous nerve of the shoulder); further, the nerve lies directly on the humerus and the groove of the radial nerve, otherwise called “[gutter]”, in this canal the nerve describes a spiral around the humerus, passing from the inside and back in the anteroposterior direction; then the nerve at the level of the outer edge of the shoulder at the border of the middle and lower third of the shoulder changes the direction of its course, turns forward and pierces the external intermuscular septum, passing into the anterior compartment of the shoulder; below, the nerve passes through the initial part of the brachioradialis muscle and descends between it and the brachialis muscle; after passing the brachialis muscle, the radial nerve crosses the capsule of the elbow joint and passes to the supinator; in the ulnar region at the level of the external epicondyle of the shoulder or a few centimeters above or below it, the main trunk of the radial nerve into superficial and deep branches; the superficial branch goes under the brachioradialis muscle on the forearm; in its upper third, the nerve is located outward from the radial artery, passes through the gap between the bone and the tendon of the brachioradialis muscle to the dorsal lower end of the forearm; here this branch is divided into five dorsal digital nerves (nn. digitales dorsales); the latter branch in the radial half of the dorsal surface of the hand from the nail phalanx of the first, middle phalanx of the second and radial half of the third fingers; the branch of the radial nerve enters the gap between the superficial and deep fascicles of the supinator and is directed to the dorsum of the forearm (the dense fibrous upper edge of the superficial fascicle of the supinator is called the arcade of Froese); penetrating through the supinator canal, the deep branch of the radial nerve is adjacent to the neck and body of the radius and then exits onto the dorsum of the forearm, under the short and long superficial extensors of the hand and fingers. The continuation of the deep branch of the radial nerve is the dorsal (posterior) interosseous nerve of the forearm - it passes between the extensors of the thumb to the wrist joint. Thus, we can distinguish four most important (from a clinical point of view) parts of the radial nerve: 1. main trunk (motor and sensory function) - at the level of the humerus, 2. superficial branch (sensory function), 3. internal branch (motor function ) and its continuation – 4. posterior (dorsal) interosseous nerve (motor and sensory function).

Muscles innervated by the radial nerve: 1. triceps brachii, ulnar muscle (their innervation is during the passage of the radial nerve in the axillary fossa, at the level of the brachioaxillary angle and in the spiral canal); 2. brachioradialis muscle, long extensor carpi radialis (their innervation is at the level of the lower third of the humerus, after the nerve passes through the external intermuscular septum); 3. short extensor carpi radialis, supinator (their innervation is at the level of the upper part of the upper third of the forearm); 4. extensor digitorum [main phalanges], extensor ulnaris (their innervation is at the level of the lower part of the upper third of the forearm); 5. Further innervation of the muscles is carried out by the dorsal (posterior) interosseous nerve: longus muscle abductor pollicis, extensor pollicis brevis, extensor longus thumb, extensor of the index finger, extensor of the little finger (their innervation is at the level of the middle third of the humerus, after the nerve passes through the external intermuscular septum).

Sensory innervation: the posterior cutaneous nerve branches in the area of ​​the axillary exit (supplies the dorsum of the shoulder almost to the olecranon); the posterior cutaneous nerve of the forearm is separated from the main trunk of the nerve at the brachioaxillary angle or in the spiral canal (regardless of the location of the branch, this branch always passes through the spiral canal, innervating the posterior surface of the forearm); at the level of the lower part of the dorsum of the forearm, the superficial branch is divided into five dorsal digital nerves (nn. digitales dorsales), which innervate the skin of the radial half of the dorsal surface of the hand from the nail phalanx of the first, middle phalanx of the second and radial half of the third fingers; The posterior (dorsal) interosseous nerve of the forearm gives off thin sensory branches to the interosseous septum, the periosteum of the radius and ulna, and the posterior surface of the wrist and carpometacarpal joints.

Thus, the radial nerve innervates: the muscles of the posterolateral part of the shoulder, forearm and hand (which extend the shoulder, forearm, hand, fingers [main phalanges], supinate the forearm and hand, abduct the hand to the radial and ulnar sides, etc.), the skin of the back of the shoulder , forearms and hands (see diagram), etc.

Depending on the level (height) of the lesion in the syndrome of complete lesion of the radial nerve, 8 clinically significant levels of compression can be distinguished:

1. at the level of the upper third of the shoulder (humeral-axillary angle)	1. the presence of hypoesthesia on the posterior surface of the shoulder, forearm, the radial half of the dorsal surface of the hand from the nail phalanx of the first finger, the middle phalanx of the second and the radial half of the third finger; 2. weakness of forearm extension; 3. absence (decreased) reflex from the triceps brachii muscle; 4. when stretching the arms forward to a horizontal line, a “dangling” or “falling” hand is revealed (paresis of the extensors of the hand and extensors of the II - V fingers in the metacarpophalangeal joints); 5. weakness of extension and abduction of the first finger; 6. lack of supination of the arm extended at the elbow joint; 7. inability to flex the elbow of the pronated arm (paralysis of the brachioradialis muscle); 8. wasting of the muscles of the dorsal surface of the shoulder and forearm (in case of long-term damage);
2. at the level of the middle third of the shoulder (in a spiral channel)	The clinical picture corresponds to radial nerve syndrome at the level of the brachioaxillary angle with the exception of: 1. there is no hypoesthesia on the shoulder; 2. the triceps muscle does not suffer; 3. pain and paresthesia appear on the dorsum of the arm when extending the elbow joint against resistance for 1 minute or when tapping the nerve at the level of compression;
3. at the level of the external intermuscular septum of the shoulder (most common place of compression):	see paragraph 2
4. at the level of the lower third of the shoulder (above the external epicondyle):	see paragraph 2
5. at the level of the elbow joint and the upper part of the forearm (most often in the feces of the supinator fascia, in the area of ​​the arcade of Froese):	1. the presence of night pain in the outer parts of the elbow area, on the back of the forearm, and sometimes on the back of the wrist and hand; 2. the appearance of daytime pain during manual work (especially rotational movements of the forearm - supination and pronation); 3. the presence of weakness in the hand that appears during manual work; 4. local pain on palpation at a point 4–5 cm below the external epicondyle of the shoulder; 5. positive data from the “supination test” (if pain appears on the extensor side of the forearm within 1 minute); 6. positive test extension of the middle finger (appearance of pain in the hand during prolonged – up to 1 min – extension of the third finger with resistance to its extension); 7. weakness of supination of the forearm; 8. weakness or lack of extension of the main phalanges of the fingers; 9. weakness of abduction of the first finger (while maintaining extension of the terminal phalanx of this finger); 10. impossibility of radial abduction of the hand in the plane of the palm; 11. deviation of the hand to the radial side with the wrist extended;
6. at the level of the middle or lower part of the instep support:	1. (unlike point 5) finger compression syndrome is detected at the level of the lower edge of the instep support (and not the upper); 2. paresis of the finger extensors is not combined with weakness of the forearm supinator;
7. at the level of the lower part of the forearm and at the level of the wrist:	1. numbness on the back of the hand and fingers I – III; 2. sometimes burning pain on the back of the fingers; 3. positive “tapping symptom” when tapping along the radial nerve at the level of the styloid process of the radius; 4. sometimes the presence of thickening of the superficial branch of the radial nerve in the wrist area - the appearance of a “pseudoneuroma”, digital compression of which causes pain;
8. at the level of the anatomical snuffbox (for example, with de Quervain’s disease):	1. disturbance of sensitivity in the autonomous zone of the anatomical snuffbox; 2. violation of the abduction of the first finger; 3. weakness of extension of the first finger; 4. positive “tapping symptom” along the branches of the radial nerve at the level of the anatomical snuffbox.